Locomotive diesel engines generally utilize a combustion intake turbocharger which provides combustion charge air for the engine, and which is rotatably powered by exhaust of the engine. After being compressed in the turbocharger, the combustion charge air is hot, and is in need of cooling. This cooling is supplied by a charge air cooler (sometimes also referred to as an after cooler), located downstream of the turbocharger and upstream of the engine air box combustion chamber. An example of a prior art charge air system 10 is depicted at FIGS. 1 through 3, which should be referred to respecting the following description thereof.
Referring firstly to FIGS. 1 through 2, a turbocharger 12 is interfaced with at least one prior art charge air cooler assembly 14 (two prior art charge air cooler assemblies 14′, 14″ being shown at FIG. 1). The prior art charge air cooler assembly 14 includes a heat exchange core assembly 16 having a plurality of coolant tubes 14t arranged for a four-pass coolant path coolant tube arrangement, and having, for example, 26 to 27 coolant tubes deep, with a multiplicity of fins 14f connected in perpendicular relation thereto, wherein coolant (which may be liquid water or a liquid water and anti-freeze solution) circulates through the tubes via an external coolant system 18 and thereby extracts heat of the compressed charge air A from the turbocharger 12, whereupon cooled compressed charge air A′ now passes to an engine air box combustion chamber 20.
Each prior art charge air cooler assembly 14, 14′ further includes a cooler plenum 22, 22′ an inlet duct 24, 24′ integrally connected to the cooler plenum and an outlet duct 26, 26′ also integrally connected to the cooler plenum. The heat exchange core assembly 16 is slid into the cooler plenum 22, 22′ through a flanged opening 22a (not visible, but clearly understood from FIG. 1) and then bolted thereto at a flange 22f, 22f′ of the flanged opening 22a. Additionally, each inlet duct 24, 24′ has a flange 24f, 24f′ for being sealingly connected to a flange 28f, 28f′ of a respective outlet port 28, 28′ of the turbocharger 12; and each outlet duct 26, 26′ has a flange 26f, 26f′ for being sealingly connected to a respective flange 20f, (two such flanges being present, but only flange 20f is shown in FIG. 2) of the engine air box combustion chamber 20.
Now, referring to FIG. 2, and with particularity to FIG. 3, it will be seen that in order for the heat exchange core assembly 16 to be slidable into the cooler plenum 22, 22′, a considerable amount of peripheral open space 32 exists between the heat exchange coolant core assembly and the cooler plenum. In operation, some air AB of the hot compressed charge air A from the turbocharger 12 by-passes the heat exchange core assembly 16 and is not cooled. As a result the cooled compressed charge air A′ is actually a mixture of cooled air AC that has passed through the heat exchange core assembly 16 and the by-pass air AB, that is A′=AC+AB.
To the extent by-pass air AB exists, the prior art charge air cooler 14 does not do its job of providing cooling of the hot compressed charge air exiting the turbocharger. Additionally, to the extent that the inlet and outlet ducts are integral with the cooler plenum, ease of interconnection with external components of the engine is limited.
Accordingly, what is needed in the art is some configuration of a charge air cooler which eliminates by-pass air, and further which provides for easy interconnection with inlet and outlet components.